Flexoelectricity in bones

Author (s): Vasquez-Sancho, F.; Abdollahi, A.; Damjanovic, D.; Catalan, G.
Journal: Advanced Materials

Volume: 30, Issue 9
Pages: 1 – 14
Date: 2018

Bones have been known to generate electricity under pressure since Fukada and Yasuda’s seminal measurement of bone piezoelectricity in 1957.This piezoelectricity is thought to be essential for bone’s self-repair and remodelling properties, and its origin is attributed to the piezoelectricity of collagen (the main structural protein of bones). However, since the discovery of flexoelectricity, it is known that strain gradients can also generate voltages in materials of any symmetry. Here we have detected and quantified the flexoelectricity of bone and bone mineral (hydroxyapatite), and determined that flexoelectricity can account for bone’s electrical response to inhomogeneous deformations. In addition, we have used the flexoelectric coefficient of hydroxyapatite to calculate the (flexo)electric fields generated by cracks in bone mineral. Crack-generated electricity has been found to be large enough to be able to induce osteocyte apoptosis and thus initiate the crack-healing process, indicating a central role of flexoelectricity in bone damage repair and remodelling.



author = {Fabian Vasquez‐Sancho and Amir Abdollahi and Dragan Damjanovic and Gustau Catalan},
title = {Flexoelectricity in Bones},
journal = {Advanced Materials},
volume = {30},
number = {9},
pages = {1705316},
keywords = {bone remodeling, cracks, flexoelectricity, hydroxyapatite},
doi = {10.1002/adma.201705316},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201705316},
eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1002/adma.201705316},